[OpenIndiana-discuss] Installing OI on USB stick

[Jim Klimov]

On 2013-03-01 15:27, Reginald Beardsley wrote:
> As for something like Thumper, you shouldn't have all the disks in the same vdev anyway.  10 GB of disk space is about $0.50US.  So "wasting" a few small s0 slices in a 5-8 disk RAIDZ array is cheaper than using USB flash drives.  Also 100% allocating drives leads to the situation that a similar size drive might not work as a replacement. If the replacement is a single sector smaller, you can't use it as a replacement.


In the same? No. We usually have about 9 5-disk raidz1 sets, or so.
Gives a nice balance of IO spread over controllers and striping over
raidz sets, and leaves a spare drive.

Leaving some 10Gb for replacement size-alignment sounds pricey, but
is likely a good and reasonable "selling point" of the idea overall.
Note that these would sum up to half a terabyte of "wasted" raw
storage on such an example box, however.

 > Nothing about the disk "geometry" means anything anymore.   Back in 
4.1.1 days I measured the effects of various geometry based disk 
parameters before building filesystems. But they haven't meant anything 
for a very long time.


As for faster/slower/geometry, YMMV. My tests with dd into/out of
different offsets of raw drives showed a staircase of plateaus with
different speeds, sometimes differing 30% from top to bottom (for
fast bulk sequential IO).

Other stuff UFS allowed to tune (rotational latency, etc.) - yes, out
of touch with modern hardware, I guess. :)


Anyhow, if you adopt such layout on a larger box, and that has a
couple of spare drives, their small "rpool-size" partitions can be
dedicated as a ZIL, I guess. Sequential IO, no seeks, best case
for a HDD. And no expensive SSD wear-out for those writes you hope
you won't ever need have done (needed only to recover).

Now, what about the other 44 small partitions? ;)

//Jim